Power take-off gearing



Patented Oct. 25, 1949 UNITED STATES PATENT OFFICE 2,486,269 PowER TAKE-OFF GEARING Thomas L. Fawick, Akron, ohio Application September 8, 1945, Serial No. 615,181

2 claims. (cl. i4-777) This invention relates to gearing suitable for use as a power take-off for tractors, for example.

Its chief objects are to provide a compact gearing having a desirable speed-reduction ratio; to provide, for rendering the gearing effective, a control device not required to rotate and yet, preferably, adapted to cushion the torque; to provide, for such a gearing, a simple and effective lubricating system with provision against oil reaching frictional control parts that would be harmfully aiected by its contact, even though the control device as well as the gearing properare contained in the same compact housing; and to provide convenience and economy of assembly, disassembly and repair.

The single figure of the accompanying drawing is a fragmentary, vertical, axial section of a power take-off assembly embodying my invention in its preferred form for forward drive with two to one v speed reduction.

Referring to the drawing, the power take-o shaft I of a motor has secured thereon a iiywheel I I and an extension hub member I2 which is splined to a short hollow shaft I3. On the shaft I3 is secured a bevel gear I4 which is one of the coaxial gears of a differential gearing. v

A driven shaft I5 is journaled in the short, hollow shaft I3, by means of a bronze bushing I3a and a roller bearing I3b, and at a distance from the latter, by means of a radial-and-thrust bearing I6, is journaled in a stationary housing which comprises members I'I and I8, of which the latter is secured by bolts such as the bolt I9 to the crank-case or housing 20 of the motor, the gear casing member I8 being provided with a centering shoulder 2I.

The driven shaft I5 projects from the gearhousing and is adapted to have a belt-pulley or the like (not shown) mounted upon its projecting portion.

The construction as thus far described is such that the power take-off mechanism and its housing can be handled as a unit for mounting and dismounting it with relation to the motor housing, the splines of the shaft I3 mating and unmating with those of the hub member I2 as the centering shoulder 2| of the gear-housing member I8 is moved into or out of the motor housing 20.

Spaced from and facing the bevel gear I4, the other coaxial gear 22 of the differential gearing is secured upon the inside hub projection of a bell-shaped gear-housing member 23 which has the driven shaft I5 journaled within it, with a 2 naled within the housing member I8 by means of a radial-and-thrust bearing 25, one of the races of which is provided with a deformable cushionmember I8.

This brake embodies the invention of my U. S. Patent No. 2,237,864. The present embodiment comprises an annular metal base member 30 bolted at one of its annular margins to an inner face of the housing member I8 and having vulbronze bearing 24 interposed, and ls itself jour- 55 canized to its inner face an annular bag 3I adapted to be inwardly distended, toward the axis of rotation, Aby pressure fluid conducted into it through a conduit 32.

The bag is composed of rubber or the like reinforced with cords 33, its construction being substantially that of a pneumatic tire except that the bag is of pronouncedly flat cross-sectional form, so that with a given fluid pressure per square inch it will provide a strong total brake-engaging pressure.

Mounted upon the inner periphery of the bag is a circumferential set of Wear shoes, such as the shoe 34, adapted to engage the drum 29, each shoe being secured to a base-plate 35 of U-shape which straddles the tread portion of the bag and is anchored thereto by pins, such as the pin 36, extending through the rubber or the like and through the side flanges of the base plate.

The bag preferably has oppositely bulged, freely-flexing and ltorque sustaining-and-cushioning side walls and for giving them free action, without excessively localized lexure, but with small internal fluid-capacity for the bag, for quick engagement and disengagement of .the brake, the chamber in the bag is given U-shape in cross-section by the presence of a ller rib 31 which extends throughout the great-circle of the bag except that at the position of the entrance of the conduit 32 into the bag the rib is transversely grooved, as shown at 38, for free lateral flow of the incoming or outgoing fluid.

Mounted between and meshes with the coaxial gears I4 and 22 of the differential gearing is a circumferentially spaced set of bevel gears such 4I projecting from a spider hub 42 which is splined upon the driven shaft I5. Each of the gears 39 has a radial-and-thrust bearing 43 interposed .between it and a bearing cup 44 secured on the outer end of the arm 4I, so that excessive frictional resistance does not result from outward pressure of the gears 39 resulting from centrifugal force or any other cause.

The construction as thus far described is such that with the ily-wheel Il rotating, full engagement of the brake with the drum 39 causes the shaft I5 to be driven in the same direction as the motor-shaft III and gear I4 but at only half of their angular speed. Release of the brake permits the drum 28 and its gear 22 to rotate freely in the direction opposite to that of the shaft I and gear I4, so that the spider 42 and shaft I5 are not compelled to rotate.

The oil-distributing system comprises an inlet hole 45 leading, from a coupling socket in the outer face of the housing member I1, to an annular space 46 between the shaft I5 and the hub of the member 23, to which the housing member I1 is sealed by respective oil seals 41, 48 so that oil can be forced under pressure to lubricate the bearing 24 and also into radial holes 49, 49 in the shaft I5 which lead to an axial hole 50 in said shaft.

A branch hole 5I leads from the inlet hole 45 to the bearing I6 and beyond that bearing an oil revolution of the spider. as the spider is always rotating whenthe gearing is under load.

Any or all of the oil-seal and gasket members can comprise any one of the many well known oil-resistant rubber substitutes such as polymerized vinyl chloride or di-chlorbutadiene, and the same applies also to the distensible bag, but

' the bag preferably is formed primarily of natural rubber, for durability at elevated temperatures, even though it is subject to deterioration by oils contacting it.

In the appended claim the words "fulcrum gear are used as applying to the gear 22 or its equivalent. Whenever the gear 22 is functioning,

to effect drive of the shaft I5, it constitutes a non-rotating fulcrum for the action of each of the gears 39 in the latters reception of force from the gear I4 and transmission of it to the arm 4I.

The construct-ion as described is subject to modification without sacrifice of all of the advantages set out in the above statement of objects and without departure from the scope of the appended claims.

I claim:

l. A power transmitting mechanism comprising a stationary outer housing, two coaxial bevel gears facing each other within said housing, coaxial driving and driven shafts having parts of them within, and journaled with relation to, said outer housing, one of said shafts having one of the coaxial gears secured thereon and the other havseal' 52 is interposed between the driven shaft I5 v and an end cap I1a of the housing structure.

From the axial hole 50 in the driven shaft I5 radial holes such as the hole 5I lead'to splines of the shaft I5 and of the differentialispider and each spider arm is formed with a radial hole 54 in extension of one of the holes 53, with a transverse hole 55 leading to the 40, and with a pair of transverse holes 5558'leading to the outer face of the spider-arm .positions spaced inwardly from the inner ends of the spiders gears ss, so that ou win be supplied te the teeth of au of the gears and to the bearings 43, 28 and I3b.

The gear-housing members 23 and 21 are sealed to each other by a gasket 51 and respectively they are sealed to the housing member I8 by an oilseal 58 and to the ily-wheel's extension hub I2 by an oil-seal 58, so that oil can not reach the friction face of the drum 29 or the dstensible bag 8|, permissibly of rubber, which coacts with it.

The shaft I0 is sealed to its extension hub I2 by a gasket IIIb so that oil forced through radial hole 53a in the shaft I5 and through th'e bearing f lla can flow only to the space within the gear members 23, 21 can be kept completely filled with oil, or a less quantity of oil can be maintained therein, with each er the bearings n dipping into A oil in the lower part of thejgear-case at each ing a radial arm extending between the coaxial gears, a bevel gear journaled on said arm and meshed with the coaxial gears, a rotatable ninner housing securedV to the other one' of the coaxial gearsA and surrounding all of said gears, oil-sealing means interposed operatively ,between the said inner housing and the respective shafts. and friction-brake means within the outer housing and surrounding said inner housing substantially at the position of the gears axially loi the assembly, for stopping and releasing said inner housing, the inner housing. oil-sealing means and shafts defining a substantially closed chamber containing the gears.

2. A mechanism as defined in claim 1 including stationary oil-drainage means in communication with the space within the inner housing but, be-

A cause of the oil-sealingv means defined, not in communication with the space surrounding the friction-brake means.

`THOMAS L. FAWICK. REFERENCES crrEn The following references are of record in the file of this patent:

UNITED STATES PATENTS 

